MediumFix available
expat — security advisory
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
- Products
- expat
- Affected versions
- 2.5.0-1, 2.5.0-1+deb12u1, 2.5.0-1+deb12u2, 2.7.1-2, 2.7.2-1, 2.7.3-1, 2.7.3-2, 2.7.4-1, 2.7.5-1, 2.8.0-1, 2.8.0-2, 2.8.1-1, 2.8.2-1~deb13u1
- Fixed versions
- 2.5.0-1+deb12u3, 2.8.2-1, 2.8.2-1~deb13u1
- CVEs
- CVE-2026-56412
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:17 UTC · Revision 2
Source evidence
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
osv:DEBIAN-CVE-2026-56412
expat
Fixed versions: 2.5.0-1+deb12u3
expat
Fixed versions: 2.8.2-1~deb13u1
expat
Fixed versions: 2.8.2-1
Complete source record
{
"id": "7c21bbfbe6387efc53d7cf0f0be7225b925a113af944877acaff651ea9e10567",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-56412",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-56412",
"summary": "libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.",
"evidence": "osv:DEBIAN-CVE-2026-56412",
"products": [
{
"name": {
"value": "expat",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.5.0-1+deb12u3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "2.5.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.0-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.0-1+deb12u2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "expat",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.8.2-1~deb13u1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "2.7.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.3-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.5-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "expat",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.8.2-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "2.7.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.3-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.3-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.4-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.5-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.2-1~deb13u1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-56412",
"aliases": [
"DEBIAN-CVE-2026-56412"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.5.0-1+deb12u3"
}
]
}
],
"package": {
"name": "expat",
"purl": "pkg:deb/debian/expat?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.5.0-1",
"2.5.0-1+deb12u1",
"2.5.0-1+deb12u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-56412.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.8.2-1~deb13u1"
}
]
}
],
"package": {
"name": "expat",
"purl": "pkg:deb/debian/expat?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.7.1-2",
"2.7.2-1",
"2.7.3-1",
"2.7.3-2",
"2.7.4-1",
"2.7.5-1",
"2.8.0-1",
"2.8.0-2",
"2.8.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-56412.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.8.2-1"
}
]
}
],
"package": {
"name": "expat",
"purl": "pkg:deb/debian/expat?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.7.1-2",
"2.7.2-1",
"2.7.3-1",
"2.7.3-2",
"2.7.4-1",
"2.7.5-1",
"2.8.0-1",
"2.8.0-2",
"2.8.1-1",
"2.8.2-1~deb13u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-56412.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T11:47:31.017285240Z",
"provider": "osv",
"upstream": [
"CVE-2026-56412"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-56412"
]
},
"related_cves": [
{
"value": "CVE-2026-56412",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 450801,
"published_at": "2026-06-21T17:16:44.657+00:00"
}